Device for eliminating the front and end trimmings from series of rolls and for sorting the rolls

ABSTRACT

The device for removing front and end trimmings in a series of aligned rolls comprises: at least one continuous flexible suction conveyor ( 13 ); a suction system ( 3 ) associated with the conveyor so as to generate a suction through openings ( 13 A) in the conveyor; a device for eliminating trimmings along a roll transfer path; a device receiving rolls from the conveyor. The receiver comprises at least two alternate paths for the rolls, which are arranged in sequence along the conveyor ( 13 ) and onto which the rolls may be alternately sorted.

TECHNICAL FIELD

[0001] The present invention relates to a device for removing front andend trimmings from series of aligned rolls obtained, for example, bytransversely cutting logs of wound web-like material.

[0002] Devices of this kind are commonly used in the paper convertingindustry in order to eliminate the trimmings before packaging of therolls of paper material, such as rolls of toilet paper, paper towels andthe like.

STATE OF THE ART

[0003] In the production of rolls of wound web-like material, forexample rolls of toilet paper, paper towels or other paper material,winding of the web-like material into so-called logs, i.e. rolls with adiameter equal to that of the finished rolls and with a considerableaxial length, is performed. The latter are then cut perpendicularly totheir axis by means of so-called saw machines.

[0004] During cutting of the logs, a front trimming and an end trimmingare generated and must be eliminated before the subsequentroll-packaging operation and possibly recycled. In order to eliminatethe trimmings, various devices of a mechanical type have been developed.More recently, devices which perform elimination of the trimmings fromthe series of cut rolls with the aid of pneumatic means have beendeveloped.

[0005] An example of a pneumatic device for eliminating trimmings isdescribed in U.S. Pat. No. 5,475,917. In one of the embodimentsdescribed in this publication, the front and end trimmings of the seriesof rolls cut from the logs and subsequently fed to the device areeliminated by interrupting in a suitable zone the suction exerted by aflexible suction conveyor which removes the rolls from a feeder andtransfers them to a receiver. By suitably positioning and dimensioningthe non-sucking zone and using a conveyor of suitable length, it ispossible to ensure that the front and end trimmings are always locatedin the position where the suction through the conveyor is interrupted.

[0006] Another system for eliminating the trimmings based on the use ofpneumatic means in combination with mechanical means is described inU.S. Pat. No. 5,458,033. This system envisages a suction conveyordivided into three portions, a central portion and two side portions,which may be staggered with respect to each other.

[0007] In the production and packaging of rolls of wound strip-likematerial there also exists the need to sort the rolls onto separateconveyors depending on the specific requirements during the processingphase. U.S. Pat. No. 4,033,862 describes a sorting device which is ableto receive, at its input, a series of rolls from which the trimmingshave already been eliminated, in order to distribute them in accordancewith a predetermined criterion on a series of conveyors arranged insuccession. This device is not able to eliminate the trimmings.

OBJECTS AND SUMMARY OF THE INVENTION

[0008] The object of the present invention is to provide a device forremoving the front and end trimmings in a series of aligned rolls, forexample rolls of paper or other web-like material, obtained by cuttingthe logs, which also allows sorting of the rolls to be performed.

[0009] This and further objects and advantages, which will become clearto persons skilled in the art from reading the text which follows, areobtained with a device in which a conveyor associated with a system forretaining the rolls transfers the rolls, once the trimmings have beeneliminated from them, onto a receiver which comprises at least twoalternate paths arranged in sequence along the conveyor itself and inwhich the conveyor is equipped with a sorting system for releasing therolls alternately to either one of the paths of the receiver.

[0010] In a practical embodiment, the conveyor is a suction conveyorassociated with a retaining system of the suction type for retaining therolls. As a result it is possible to obtain a compact device and aparticularly simple and low-cost configuration of the sorting meanswhich allow transfer of the rolls to either one of the alternate paths.Elimination of the trimmings is also obtained in a simple manner.

[0011] The conveyor with the associated suction system may be positionedso as to be arranged above the rolls which are fed to it, so as toretain the latter from above. However, this is not strictly necessarysince the pneumatic grip exerted by the suction means may also beoriented non-vertically, provided that it is opposed by the force ofgravity, due to the effect of which the trimmings are discharged. Forexample, the conveyor may be located laterally with respect to therolls.

[0012] In a practical embodiment, the suction system associated with theconveyor comprises at least one first and one second suction member. Thetwo suction members are arranged in series along the extension of theconveyor and the sorting system acts at least on the second suctionmember arranged downstream of the first suction member with respect tothe direction of advancing movement of the conveyor, so as to activateor deactivate alternately the second suction member. In this way, whenit is required to sort the rolls from the device for removing thetrimmings onto the first of the alternate paths (i.e. onto the pathwhich is first encountered by the rolls fed by the conveyor) the secondsuction member is deactivated. In this way, the rolls are necessarilyreleased by the conveyor to the first of the said alternate paths. Whenit is desired to release the rolls onto the second alternate pathencountered during the advancing movement of the conveyor, the secondsuction member is activated, such that the rolls are retained by theconveyor until they reach the point where they may be released to thesecond alternate path.

[0013] The idea explained above may be extended to a configuration withmore than two alternate paths and consequently with more than twosuction members arranged in succession along the roll conveyor. In anycase, the rolls will be released to that path of the receiver which islocated immediately downstream (with respect to the direction ofadvancing movement of the rolls) of the last active suction member.

[0014] The various suction members may consist of successive portions ofa wall along which the conveyor travels. The wall portion furthestdownstream—corresponding to the suction member which must be deactivatedwhen the rolls must be released to the first alternate path—has,associated with it, an intercepting member for intercepting the suctionthrough this wall portion. When there are more than two alternate paths,the wall portions along which the conveyor travels and which may beequipped with intercepting members are at least equal to the totalnumber of alternate paths less one. Each intercepting member may beactuated independently of the others.

[0015] According to a particularly advantageous embodiment of theinvention, the suction system comprises a suction box with a wall orwalls along which the conveyor travels. Suction openings are formedalong the wall or walls and are divided into a number of groupscorresponding to the number of alternate paths along which the rolls fedby the conveyor may be discharged. The various wall portions, with theexception, where applicable, of the first one, are equipped withsuitable intercepting members. In practice, the suction box may besingle and interception of the openings of the second group of openingsis obtained by simply actuating an intercepting system, for example alaminar valve. However, according to a preferred embodiment, the suctionbox is divided into a number of chambers corresponding to the number ofalternate paths provided in the roll receiver. In this case the firstchamber may be constantly in communication with the respective series ofopenings of the first group. In the second chamber, and where applicablein each successive chamber, a respective intercepting member forintercepting the suction through the respective openings is provided.

[0016] In general, interception may occur by means of a valve or a tapon a suction duct which connects the suction chamber to a suction deviceor equivalent. In practice, however, in order to accelerate the responseof the system to actuation of the intercepting member, the latter isadvantageously formed by a laminar valve which slides over the openingsof the respective chamber or using some other equally rapid operatingsystem.

[0017] In this way immediate interception or opening of the suction inthe respective group of openings is obtained.

[0018] In the detailed description which follows, a specific andparticularly advantageous system for eliminating the trimmings,resulting in a versatile and compact device, is described. It must beunderstood, however, that the specific type of system for eliminatingthe trimmings and its structural and functional characteristics are notcritical for the realization of the present invention. The trimmings maybe eliminated also using means different from the specific meansdescribed, for example using a system of the type known from the stateof the art or other equivalent system. Solely the presence of a suctionsystem for gripping the rolls is of relevance for the purposes of thepresent invention.

[0019] Further advantageous features and embodiments of the deviceaccording to the invention are indicated in the accompanying dependentclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The invention will be better understood with reference to thedescription and the accompanying drawing, which shows a practicalnon-limiting example of said invention. In the drawing:

[0021]FIG. 1 shows a side and partially sectioned view of the device ina first operating condition;

[0022]FIGS. 2 and 3 show local cross sections along II-II and III-III inFIG. 1;

[0023] FIGS. 4 to 6 show three successive operating phases of the deviceduring elimination of the trimmings; and

[0024] FIGS. 7 to 10 show three successive operating phases of amodified form of the device during elimination of the trimmings and across section of the modified device, similar to the cross section inFIG. 2.

DETAILED DESCRIPTION OF AN EMBODIMENT

[0025] The device comprises a pair of side walls 1, between which asuction box 3 divided into two chambers 3A and 3B by a separation baffle5 is arranged. The chamber 3A is connected to a suction duct 7A, whilethe chamber 3B is connected to a suction duct 7B. The separation baffle5 may be omitted and the suction duct may be single instead of double. 9denotes the end wall of the suction box 3, which wall is divided intotwo portions 9A and 9B corresponding to the chambers 3A and 3B intowhich the suction box is divided. Openings 11A are formed in the wall9A, while openings 11B are formed in the wall portion 9B.

[0026] One or more flexible conveyors 13 travel along the bottom surfaceof the wall 9. The number of flexible conveyors 13 (two in the exampleillustrated) corresponds to the number of roll feed channels. The twoconveyors 13 are arranged parallel to each other, as shown in the crosssection in FIG. 2, and are arranged so as to receive simultaneously tworows of rolls supplied from a two-channel saw machine (not shown).

[0027] The flexible conveyors 13 are driven around a first idle roller15 and a second motorized roller 17. The roller 17 receives the movementfrom a motor which, in the example illustrated, is indicated by 19 andarranged coaxially with the roller 17.

[0028] Each flexible conveyor 13 has openings 13A which extend along itswhole extension. The openings 13A are flanked by lips 13B which alsoextend along the whole extension of the conveyor 13. In the bottom zoneof the path of the conveyors 13, where the latter make contact with thebottom surface of the wall 9 of the suction box 3, a suction obtained bymeans of the vacuum generated inside the chambers 3A and 3B is producedthrough the openings 13A. In a manner known per se, the suction exertedthrough the openings 13A has the function of retaining the rolls fed tothe conveyors 13 in the manner which will be described below.

[0029] Chain wheels 21 are also supported idle, by means of suitablebearings, on the shaft 23 on which the roller 15 is supported. Similarchain wheels are mounted on the shaft 24 supporting the roller 17.Assembly is such that the motor 19 which causes rotation of the roller17 does not act on the chain wheels mounted on said shaft 24, the latterwheels being supported idle and thus being able to be actuated with anactuator different from and independently of the motor 19. Another twopairs of chain wheels, denoted by 27 and 28, are also mounted betweenthe side walls 1.

[0030] Respective chains 31 are driven around the chain wheels andextend along a closed path, the bottom section of which is approximatelyparallel to the path of the conveyors 13 in the zone where the lattermake contact with the external surface of the bottom wall 9 of thesuction box 3.

[0031] Two membrane obturators 33A and 33B which are impermeable to airextend between the two chains 31 which are parallel to each other. Thetwo membrane obturators 33A and 33B are located in two oppositepositions along the path of the chains 31.

[0032] The movement of the chains 31, and therefore of the associatedmembrane obturators 33A and 33B, is obtained by means of a motor 35associated with one of the shafts of the chain wheels, in the caseillustrated with the shaft on which the chain wheels 28 are keyed.

[0033] The movement of the chains 31 is indicated by the arrow f31,while that of the conveyors 13 is indicated by the arrow f13.

[0034] A roll feeder 41 is located in the inlet zone of the device. Therolls R are fed in series, each series having a front trimming RT and anend trimming RC representing the portions of surplus material which mustbe eliminated by means of the device described. The feeder 41 isgenerally shown as a continuous conveyor, but may assume any suitableform and may be suitably equipped with thrusters which facilitatefeeding of the series of rolls. The arrangement is known per se andvarious alternatives are available for the person skilled in the art.

[0035] The device also comprises a roll receiver consisting, in theexample illustrated, of two alternative paths defined by a firstflexible conveyor member 45 and by a second flexible conveyor member 47.The flexible conveyor members 45 and 47 are actuated by the same motor19 which operates the conveyors 13, by means of a belt drive 49, 50.

[0036] Each of the flexible conveyor members 45, 47 has, in the exampleillustrated, at least one section approximately parallel to the bottomwall 9 of the suction box 3 and therefore to the respective section ofthe conveyors 13 making contact with the external surface of said wall9. The arrangement of the flexible conveyor members 45, 47 with respectto the conveyors 13 is such that, along the feed path of the rolls Rtransported in the direction of the arrow fR by the conveyors 13, saidrolls encounter firstly the flexible conveyor member 45 and onlysubsequently the flexible conveyor member 47.

[0037] A laminar valve 53 equipped with openings 55 and capable ofmoving in an alternating manner in the direction of the double arrow f53so as to cause, respectively, the openings 55 to communicate with theopenings 11B or be staggered with respect to the latter is arrangedinside the chamber 3B of the suction box 3. For this purpose, theopenings 55 and 11B have substantially the same amplitude and a similarshape. The laminar valve 53 therefore allows the openings 11B tocommunicate with the chamber 3B or to intercept said openings 11B,interrupting the suction through them, effected via the duct 7B.

[0038] Operation of the device described hitherto is as follows (see inparticular FIGS. 4 to 6).

[0039] The feeder 41 feeds series of rolls R underneath the bottomsection of the conveyor 13. Since the feeder 41 extends right underneaththe suction box 3 and since it is positioned so that the fed rolls R arelocated with their upper part making contact with the lips 13B of therespective conveyor 13, the suction generated through the openings 13Aof the conveyors 13 retains the rolls which form a seal against saidlips 13B. Consequently, the rolls R are transferred in the direction ofthe arrow fR toward the receiver.

[0040] If the laminar valve 53 is located in a position such as to closethe openings 11B in the portion 9B of the wall 9 corresponding to thesuction chamber 3B, the suction and therefore the retaining effect onthe rolls R ceases opposite the first flexible conveyor member 45.Consequently, the rolls R are released to the flexible conveyor member45 and further conveyed in the direction of the arrow f45 towardfollowing processing stations. This is the situation illustrated inFIGS. 4 to 6.

[0041] If, on the other hand, the laminar valve 53 is in a position suchas to keep the openings 11B open and in communication with the suctionchamber 3A, the retaining effect due to suction on the rolls R ismaintained as far as the end zone of the suction box 3, opposite theflexible conveyor member 47. The rolls R are in this case released bythe conveyor 13 to the flexible conveyor member 47 which transfers themin the direction of the arrow f47 toward a further processing station.This is the situation illustrated in FIG. 1.

[0042] Elimination of the front and end trimmings is obtained as follows(FIGS. 4 to 6): the position of the end trimming RC of a first series ofrolls and the front trimming RT of the following series is known fromthe data supplied by the saw machine arranged upstream of the device(and not shown). It is therefore possible, by means of the motor 35, tocause the movement of the chains 31 and the membrane obturators 33A and33B so that one of the two obturators 33A, 33B is arranged between thebottom section of the conveyors 13 and the end trimming RC and fronttrimming RT when the latter are positioned by the feeder 41 underneaththe suction box 3. In this embodiment, the distance between thetrimmings RC and RT corresponds approximately to the length of theobturators 33A, 33B. Consequently, the retaining suction effect is notexerted on the trimmings RC and RT, which fall toward a collection zonein the space between the terminal end of the feeder 41 and the start ofthe flexible conveyor member 45. A container or a suitable conveyor (notshown) collect and/or convey away the trimmings.

[0043] The movement of the chains 31 and consequently the obturators33A, 33B continues—at the same speed as the conveyors 13—until theobturator which has intercepted the suction opposite the trimmings justdiscarded is positioned beyond the suction box 3. From this position,the membrane obturators 33A, 33B will be displaced by means of movementof the chains 31 so as to be positioned for subsequent operation inorder to eliminate successive front and end trimmings. The presence oftwo obturators allows one or other of the two obturators to be usedalternately, resulting in more rapid positioning of said obturators inpreparation for operation thereof.

[0044] FIGS. 7 to 10 show, in three different and successive operatingconditions, a modified embodiment of the invention. Similar numbersindicate parts which are the same as or correspond to those in theprevious embodiment. The device as claimed in FIGS. 7 to 9 differs fromthe previous device in that two pairs of chains 31A, 31A and 31B, 31B,which are driven around respective chain wheels and which are visible inparticular in the cross section shown in FIG. 10 (equivalent to thecross section shown in FIG. 2), are provided. A first membrane obturator33X is attached to the chains 31A driven around the wheels 21A and thewheels 19A, 27A and 28A, while a second membrane obturator 33Y isattached to the chains 31B. The two pairs of chains 31A, 31A and 31B,31B are actuated by independent motors denoted by 35A and 35B in FIGS. 7to 9. In this way, the two pairs of chains and consequently the twomembrane obturators may be displaced along the path defined by saidchains in an independent manner by means of the two motors. As a result,it is possible to obtain certain advantages which will emerge clearlyfrom the description of operation, with reference to FIGS. 7 to 9.

[0045]FIG. 7 shows the instant in which the end trimmings RC reach thesuction conveyors 13. The two membrane obturators 33X and 33Y arelocated adjacent to each other, with the front edge of the membraneobturator 33X in a position such as to come into contact with the endtrimmings RC. When the end trimmings RC are situated in front of themembrane obturator 33X, the latter begins to move in the direction offeeding of the rolls, at the same speed as the latter, being controlledtherein by the respective chains 31A and by the motor 35A. FIG. 8 showsthe first phase of movement of the obturator 33X which accompanied theend trimmings RC to the falling zone.

[0046] Vice versa, the chains 31B and the membrane obturator 33Y mayremain at a standstill. The advancing movement of the membrane obturator33Y will start in synchronism with the advancing movement of the fronttrimmings RT of the following series of rolls. FIG. 9 shows the instantin which the obturator 33X has reached and surpassed the pair of wheels19A, while the membrane obturator 33Y is advancing in front of the firstroll of the following series, which has yet to reach the point ofseparation from the pneumatic retaining system. The membrane obturator33X may advance to this point at high speed until it reassumes theposition shown in FIG. 7 in order to start a following roll dischargecycle, independently of the speed of advancing movement of the membraneobturator 33Y, owing to the use of two independent driving systems forthe two obturators.

[0047] The substantial advantage which is obtained with thisconfiguration compared to that described previously consists in the factthat the distance between the end trimmings RC and the front trimmingsRT may be any and is not dependent upon the longitudinal dimension ofthe obturators 33X, 33Y. In fact, these two obturators act independentlyof each other on the end trimmings and on the front trimmings,respectively. Any greater or lesser distance between the end and thefront of successive series of rolls is compensated for by simplydelaying more or less the start of the movement of the second obturator33Y with respect to the first obturator 33X. As can be seen from FIGS. 7to 9, in fact, the distance between the front and end trimmings isgreater than the sum of the longitudinal lengths of the two obturators.Nevertheless, having delayed the start of the advancing movement of thesecond obturator with respect to the first one, it has been possible todischarge both the front trimmings and the end trimmings.

[0048] Moreover, since the first obturator 33X, once it has reached theposition in which the rolls leave the pneumatic retaining system, isable to advance at a speed greater than and independent of the speed ofthe rolls, in this configuration it is not necessary to provide on thesame pairs of chains several obturators which act alternately insuccessive operating cycles, as instead envisaged in the precedingconfiguration. In fact, there is sufficient time for the obturator 33Xto position itself again at the working point while the obturator 33Y isstill advancing at the (slower) speed of the rolls. Moreover, the activeoperating phase of the obturator 33X is able to start even before thesecond obturator 33Y is correctly positioned in the operating positionfor eliminating the front trimmings of the following series of rolls.

[0049] The system thus configured has an even greater flexibility andadaptability to any operating condition, it being possible to programfrom a keyboard or other suitable interface all the movements of theobturators so as to allow adaptation to any size of the rolls and to anylength of the series of rolls as well as to any distance betweensuccessive series of rolls.

[0050] The example in FIGS. 7 to 9 shows a configuration in which therolls are sorted onto the flexible conveyor 47, as an alternative to theprevious configuration where the conveyor 45 was active. The system fordischarging the trimmings may also operate without the means for sortingonto two or more roll sorting and discharge paths, as may the sortingsystem also operate with a different system for discharging thetrimmings.

[0051] The device described, when it has both the sorting system and thesystem for eliminating the trimmings (in either one of theconfigurations described), allows simple and rapid sorting of the rollsR alternately onto the conveying member 45 or onto the conveying member47, depending on the requirement in each case in the production cycle.The transition from one of the two flexible conveyor members to theother may be requested, for example, depending on the type ofmanufactured article fed in each case to the device or depending on theoperating conditions of the machines downstream.

[0052] It is clear that the concept described here with reference to asystem with two flexible conveyor members 45, 47 may be furtherdeveloped by envisaging three or more flexible conveyor members arrangedin series in the direction of feeding fR of the rolls.

[0053] The device described also allows easy and rapid adaptation to thevarious sizes of the series of rolls arriving from the feeder 41.

[0054] Contrary to the devices of the prior art, in fact, the zone inwhich suction through the conveyors 13 is interrupted in order to allowdischarging of the trimmings may be positioned as required, beingdefined by the membrane obturators 33A, 33B or 33X, 33Y. This allows, inaddition to a high degree of flexibility, also a considerable limitationof the overall dimensions, since the length of the conveyors 13 on theone hand and of the chains 31 on the other hand are not dependent uponthe dimensions of the rolls and upon the overall length of the series ofrolls fed to the device, contrary to that which occurs in the devices ofthe prior art.

[0055] The adaptation of the device to the diametral dimension of therolls is obtained—in a manner known per se—by means of heightwiseadjustment of the side walls 1 with respect to the flexible conveyormembers 45, 47 and the feeder 41.

[0056] It is understood that the drawing shows only a simplificationprovided by way of a practical demonstration of the invention, the formand dimensions of said invention being able to vary without therebydeparting from the scope of the idea underlying said invention.

1. A device for removing front and end trimmings in a series of aligned rolls, comprising: at least one continuous flexible conveyor; a retaining system associated with said conveyor for retaining the rolls on said conveyor; a device for eliminating trimmings along a roll transfer path; a device for receiving the rolls from said conveyor; characterized in that said receiver comprises at least two alternate paths for said rolls, arranged in sequence along said conveyor; and in that said conveyor comprises a sorting system for releasing said rolls alternately to either one of said at least two paths.
 2. Device as claimed in claim 1, characterized in that said conveyor is a suction conveyor and in that said retaining system is a suction system associated with said conveyor so as to generate a suction through openings in said conveyor.
 3. Device as claimed in claim 2, characterized in that said suction system comprises a first suction member and at least one second suction member arranged downstream of the first suction member with respect to the direction of advancing movement of said conveyor and in that said sorting system acts on said at least one second suction member so as to activate or deactivate alternately said at least one second suction member.
 4. Device as claimed in claim 3, characterized in that said first and said at least one second suction member consist of respective portions of a wall along which said conveyor travels and in that at least the wall portion furthest downstream has, associated with it, a respective intercepting member for intercepting the suction through said wall portion.
 5. Device as claimed in claim 2 or 3 or 4, characterized in that said suction system comprises a suction box with a wall equipped with suction openings, along which said conveyor travels, and in that said suction openings are divided into at least two groups arranged in succession in the direction of advancing movement of said conveyor, an intercepting member for intercepting said openings of said at least one second group of openings being provided.
 6. Device as claimed in claim 5, characterized in that said suction box is divided into at least one first and one second chamber arranged in series, the openings of said first group communicating with the first chamber and the openings of said second group communicating with the second chamber.
 7. Device as claimed in claim 6, characterized in that a laminar valve is arranged slidably inside said second chamber so as to close the suction openings of said second group.
 8. Device as claimed in one or more of the preceding claims, characterized in that said receiver comprises a first flexible conveyor member defining said first path and a second flexible conveyor member defining said second path.
 9. Device as claimed in claim 8, characterized in that said two flexible conveyor members have a movement with at least one component parallel to the direction of advancing movement of the said conveyor.
 10. Device as claimed in claim 9, characterized in that said first flexible conveyor member has a section approximately parallel to the conveyor and a section inclined and diverging with respect to said conveyor.
 11. Device as claimed in claim 10, characterized in that said inclined section of the first flexible conveyor member extends as far as underneath the second flexible conveyor member. 